Performance of CuOx–neutral Al2O3 sorbents on mercury removal from simulated coal combustion flue gas

Abstract Copper based sorbents are used to control mercury emissions in coal-fired flue gas. CuO x impregnated on neutral Al 2 O 3 (CuO x –Al 2 O 3 ) sorbents were found to enhance catalytic oxidation of elemental mercury in the presence of hydrogen chloride (HCl). The Hg 0 oxidation rates increased along with the increasing HCl concentration and temperature. The mercury oxidation rates were over 65% in the presence of 50 ppm HCl and the mercury adsorption amounts were over 75% in the early stage of the mercury removal process. CuO x –Al 2 O 3 sorbents demonstrated good mercury removal capacity. The effect of HCl is due to the formation of active chlorine. CuO x –Al 2 O 3 sorbents also have excellent sulfur resistance in the presence of HCl. A mixture of CuO x –Al 2 O 3 and activated carbon can remove more than 90% Hg 0 with a lower mercury removal cost for industrial applications. The characterizations of the CuO x –Al 2 O 3 sorbents were measured suggesting CuO x species work as catalysts via the redox shift between Cu 2 + and Cu + . The mercury oxidation mechanism of the sorbents is proposed to follow the Mars–Maessen mechanism.